IgE is the major class of antibody mediating immediate hypersensitivity. In order to understand the basis of human allergic disorders, it is important to elucidate how IgE antibody production is regulated and how IgE functions in mediating hypersensitivity reactions. This research program proposes a detailed analysis, applying recombinant DNA technology, of the regulation of IgE heavy epsilon chain gene expression and of the structure of the IgE molecule as related to its function. First, attention will be directed to the control mechanisms of gene expression. Specifically, areas in the gene that might be responsible for receiving signals transmitted by regulatory molecules to IgE-synthesizing cells will be identified. This will be approached by transfecting myeloma cells with epsilon chain recombinant DNA containing specific deletions and analyzing the susceptibility of these myeloma cells to suppression by IgE- specific regulatory factors. Second, the possibility of suppression of IgE synthesis in IgE- producing cells by anti-sense RNA complementary to epsilon mRNA will be explored. If the experiments are successful, transgenic mice microinjected with DNA coding for anti-sense epsilon RNA will be generated. The production of mice with a diminished IgE response would suggest the possibility of using gene therapy for human allergy in the future. Third, establishment of the IgE structure-function relationship will be pursued. Expression of various epsilon chain domains in E. coli, construction of IgE with selected domains deletions, and generation of IgE mutants with specific amino acid deletions or substitutions will be performed. These recombinant products should facilitate the identification of determinants important for the binding to or induction of various IgE receptors. The long-term goals of this research are: 1) establishment of a precise knowledge of the intricate network of genetic, cellular and molecular components involved in the regulation of IgE production; and 2) the development of methods or agents for the treatment of human disorders.